In data presentation of computing
systems and applications, when a user click the submit button on the form, the
name-value pair of each form is sent because it is an open-ended data structure
that allows future extension without altering existing code or data.
For the view of Exercise 4.18, explain why the database system would not allow a tuple to be inserted into the database through this view.
For reference
For the database of Figure 4.12, write a query to find the ID of each employee with no manager. Note that an employee may simply have no manager listed or may have a null manager. Write your query using an outer join and then write it again using no outer join at all.
OUTER JOIN
select e.ID from employee e left outer join manages m on e.ID = m.ID
where m.manager_id is null;
NO OUTER
select e.ID from employee e where e.ID not in (select m.ID from manages m) or e.ID in (select m.ID from manages m where m.manager_id is null);
Answer:
Automation testing can be used for:
<u>Input-output test
:</u> If the main function of your software is to transform input data into output data you can configure a new test by providing a new input/output pair, then the test will check to see if the output matches with the expected values.
<u>Unit test
:</u> This test is a script to check the return values of a specific code by initializing it and calling his methods. This is a part of a test-driven development process.
<u>Integration test
:</u> This test is a code level script that does a complete check process involving multiple objects. For example, you might make a test for “buy a product” which checks to see if the database is updated, if the data is correct of the person is correct, and if the person placing the order gets the right confirmation email.
<u>Smoke Tests:</u> This test is executed immediately after implementation on production to ensure that the application is still functioning.
Answer:
c h b l
color palette and a lightbulb
Answer: Concurrent programs are the programs that execute at the same point of time. They are simultaneous in nature with other concurrent programs.They are executed with the help of threads to achieve the concurrency without the issue of scheduling. They are consider long running programs.
The program that has the low execution time compared with all other programs gets executed first.If the case of no progress is seen then another thread is executed.This type of execution gives the non- deterministic situation in which the possibility of leading completion of any particular program cannot be determined.
